Quantum information processing and quantum optics with superconducting circuits

理解并最终适应环境的愿望与人类文明史本身一样古老。20世纪初量子力学的发现为这一努力开辟了一个新的前沿，这个前沿基于对控制原子和亚原子粒子行为的反直觉定律的探索。这导致了现代一些最具革命性的技术，包括微电子、激光和磁共振成像（MRI）。在更基本的层面上，我们的理解已经发展到现在可以通过实验控制单个原子的量子特性；2012年诺贝尔物理学奖认可了这项革命性的工作。这种“量子控制”实际上是在最基本的层面上对环境的控制和适应——探测和操纵单个能量量子。**尽管取得了这些显著的进步，但量子力学改变社会的潜力远未枯竭：我们目前正站在量子革命的边缘，它有望像过去的突破一样深刻。事实上，现在人们已经认识到，利用量子效应可以制造出比现有计算机强大得多的计算机。在某些情况下，这些量子计算机可能只需几天就能解决问题，而这些问题需要当今最快的计算机数十亿年才能完成。虽然实现这样的计算机是具有挑战性的，但在过去的几年里，在制造“人造”设备（例如印刷在芯片上的电路）方面取得了显著的进展，这些设备纯粹是量子力学的，并且与光的量子粒子强烈地相互作用。这个新兴的工程量子系统领域利用超导电路的微制造和微波工程的进步，实现了远远超过“自然”量子系统可能达到的量子控制水平。此外，这些人造量子系统可以自底向上设计，允许几乎无限的可能性：我们不仅仅局限于大自然提供的选择。**这项研究计划的目标是进一步推动我们对这些人造量子系统的基本理解，并找到利用其独特性质的新方法。因为这些超导装置利用的效应是我们理解量子理论的基础，这种探索将使我们对量子世界有更深入的了解，进而扩展到我们生活的世界。除了量子计算机，它还将为基于积极利用量子效应的卓越新技术打开大门。**在接下来的五年里，我们将专注于电路量子电动力学，这是我和同事首先提出的基于微制造超导电路的工程量子系统。由于该领域的许多最新进展都与它的发展有关，因此现在是研究该系统的一个激动人心的时刻。电路量子电动力学不仅是最有前途的量子计算机体系结构之一，而且还在介观物理和量子光学等不同物理领域之间架起了桥梁。在NSERC的支持下，我们将在这些设备的三个主要物理方面取得进展：1)微波频率范围内的量子光学。2)改进工程量子系统的测量。3)基于电路量子电动力学的量子信息处理。虽然该计划本质上是理论性的，但它与加拿大和世界上许多该领域的顶级实验室的实验工作密切相关。我们的研究结果将有助于实现新的量子技术，同时确保加拿大在新兴的量子革命中发挥主导作用。

The desire to understand and ultimately adapt one's environment is as old as the history of human civilization itself. The discovery of quantum mechanics in the early 20th century unveiled a new frontier for this endeavour, one based on exploiting the counterintuitive laws that govern the behaviour of atoms and subatomic particles. This led to some of the most revolutionary technologies of the modern era, including microelectronics, lasers, and magnetic resonance imagining (MRI). On a more fundamental level, our understanding has progressed to the point where experimental control of the quantum properties of individual atoms is now possible; the 2012 Nobel Prize in Physics recognized this revolutionary work. This "quantum control" is quite literally control and adaptation of the environment at its most fundamental level -- the detection and manipulation of individual quanta of energy.**Despite these remarkable advances, the potential for quantum mechanics to transform society is far from being exhausted: we currently stand on the verge of a quantum revolution that promises to be as profound as the breakthroughs of the past. Indeed, it is now recognized that quantum effects can be harnessed to create computers that would be immensely more powerful than current ones. In some cases, these quantum computers could take days to solve problems that would require today's fastest computers billions of years to complete. While the realization of such computers is challenging, the past few years have seen remarkable progress in making "man-made" devices (e.g. circuits printed on a chip) act purely quantum mechanically and interact strongly with quantum particles of light. This emerging field of engineered quantum systems uses advances in micro-fabrication of superconducting electrical circuits and microwave engineering to achieve a level of quantum control that far exceeds what is possible with "natural" quantum systems. Moreover, these man-made quantum systems can be designed from the bottom up, allowing an almost infinite range of possibilities: we are not simply limited to the options provided by nature.**The goal of this research program is to push further our fundamental understanding of these man-made quantum systems and to find new ways to exploit their unique properties. Because these superconducting devices harness effects that are at the foundation of our understanding of the quantum theory, this exploration will yield a deeper understanding of the quantum world, and by extension the world we live in. Beyond quantum computers, it will also open the door to remarkable new technologies based on actively exploiting quantum effects.**In the next five years, we will focus on circuit quantum electrodynamics, an engineered quantum system based on microfabricated superconducting circuits that was first proposed by colleagues and myself. Because much of the recent advances in the field are linked to its development, this is an exciting time to study this system. Circuit quantum electrodynamics is not only one of the most promising quantum computer architectures, it has also bridged the gap between different fields of physics, namely mesoscopic physics and quantum optics. With NSERC support we will make advances in three major aspects of the physics of these devices: 1) Quantum optics in the microwave frequency range. 2) Improved measurement of engineered quantum systems. 3) Quantum information processing with circuit quantum electrodynamics. While theoretical in nature this program is heavily connected to experimental efforts in many of the field's top laboratories in Canada and worldwide. Our findings will help in bringing new quantum technology to fruition, while assuring Canada a leading role in the emerging quantum revolution.